Hello everyone,
I have a problem with code written above, because it doesn't work as I'd like.
That code is inspired by the example called 'Ajax with XML forms' (http://dev.sencha.com/deploy/ext-4.1.../xml-form.html), when the user hits the 'Load selected customer' button a PHP script fetches a record from a MySQL database, encodes fetched data as a JSON string and then sends that string to output stream by using 'echo' instruction.
The code doesn't work as expected, because when I run it the only result I obtain is an empty form, that is a form without any fields.
I have done some debug and I'm sure that 'load_customer.php' works fine: it returns the JSON string I expect.
Any idea to fix my code ?
Thanks in advance.

Note that 'load_customer.php' is called up when the user hits the button named 'Load selected customer', I believe the problems in my code start before this event, because when I load the page on my web browser I don't obtain the form I expect.
I can only see the frame of my form, a blue horizontal line (instead of the fields of my form) and, at the bottom, the button 'Load selected customer'. When I push it, the message 'Saving Data...' is correctly shown, but fields don't appear.
In my intention, I'd like to see a form with three empty fields ('company','vat','ssn') when I load the page on my browser and then, when I hit the load button, I'd like to load required data from a MySQL db via 'load_customer.php' script.